This invention relates to the removal of small solids from flowing fluids.
There are many industrial operations, such as blast furnaces, power plants, coke oven batteries and the like, that produce by-products that are detrimental to the environment. Such by-products are, generally, fine solid particles.
One method of capturing these particles so that they may be properly processed for disposal is by means of a scrubber. The scrubber places the particles into a solution that discharges into a settling basin where separation and particle precipitation can take place.
Such installations are large and expensive and the timing depends on the influence of gravity on the particles in the solution mixture.
Scrubbers are satisfactory for entraining the discharging particles but there could be a great improvement in the equipment utilized beyond the scrubber.
Desirably such equipment should be relatively small and an in-line facility that would return the water to operations and isolate or purge the particles for a controlled disposal.
One apparatus proposed to accomplish such purpose has been termed a fluid classifier. Such apparatus functions to withdraw the liquid from a lading (mixture of liquid and solid particles) while preventing onward flow of the solid particles. The liquid, which is in most cases water, can immediately return to process and the particles will agglomerate and precipitate by designation for disposal.
One such fluid classifier is comprised of a filter element (woven wire cloth) in cylindrical or sleeve form closed at one end and open at the other end to a pump suction. This cylinder is immersed in the lading in such manner that there is relative movement between the outer cylinder surface and the lading.
Filter action is from the outside or lading side of the sleeve to the inside or pump suction connection. This relation always maintains the particles in the incoming lading volume from where they precipitate into a sump, and at the same time allows the pump to move the clean liquid to its designation.
Relative motion between the sleeve and the lading subjects the particles to conditions of dynamics and probability with the result that unless the particles can act like the liquid they will not succeed in gaining passage through the filter interstices. The size of the openings in the filter element is of capillary order.
A back-wash action for clearing the flow can be obtained by an increase in rotational speed. Such action was effective but was necessarily intermittent. A continuous clearing action which precludes the need for back-wash can be obtained with a separate pumping system that sucks a volume of lading from the surface of the adjacent rotating filter unit. A gradient suction chamber typically with a nozzle narrow for the height of the filter surface is operated at the same suction pressure as that within the filter unit, giving uniform suction the full height of the filter. It can continually act to prevent particle build-up at the filter unit influent surface without affecting the fluid classifier operation or efficiency.
The apparatus as described above has operated in the separation of solid .particles from lading, though some problems have been encountered and it is an object of the present invention to provide a new and improved fluid classifier.